Hi,
Just from the first look at it I like this one. I use javascript-mode
normaly, but js2-mode has much more features like error-checking and
folding, jump to next error. Works nicely with imenu/speedbar.
A JavaScript mode is something really missing in emacs.
Just one little drawback:
I prefere to have similar faces in all the prog modes I use. E.g.
js2-constant-face is 'gray', which I hardly can see on white background.
Normaly I use a different face for constants, that most programming
modes respect. js2-mode urges me to setup all the faces again just for
the use of this mode.